A local newspaper said the company had just announced it was to cut production after a poor logging season, although the company’s chief executive, Mauro Capozzo, said none of the company’s 450 workers had been made redundant yet.

Mr Capozzo added that the suspected assailant, a former kickboxer, had been "with us for more than 10 years - a quiet man, no other incidents involving him are known."

According to other witnesses, the gunman had begun to have noticeable psychological problems during the last year.

One employee told local media: “In the last year he has changed. He talks more to himself or talks to people who are not there.

“Often he would join in the middle of someone’s conversation. You could barely talk to him.

“He was strange but this is not something we would have ever expected.”

The Mayor of Menznau Adrian Duss said: “I am horrified. We are shocked that something like this has happened in our community.

“This is an incredible tragedy for the families and our community. What has happened is incomprehensible and makes me speechless.”

Gun ownership is widespread in Switzerland, thanks to liberal gun controls and a tradition of men keeping their military rifles after their compulsory national service.

Switzerland’s eight million citizens possess around 2.3 million firearms between them, and support for gun ownership is strong.

Questions about the country's gun-control laws have been raised after previous shootings, including the 2001 massacre of 14 officials at a local parliament meeting in Zug by a man who then turned the gun on himself.